A study suggests that an experimental, non-invasive way to assess suspicious areas in the breast -- called optical tomography -- may be able to help determine if an area is cancer or not. The suspicious areas were first identified by mammogram or breast ultrasound.
Screening mammograms save lives by finding breast cancer early, when it's most easily treated. Still, mammograms aren't perfect. They sometimes identify an abnormal area that looks like cancer, but turns out to be normal. Doctors call this false alarm a false positive. Besides the fear of a breast cancer diagnosis, a false positive usually means more tests (including biopsies) and follow-up doctor visits. The process can be very stressful and upsetting.
Sometimes when a mammogram finds a suspicious area, a breast ultrasound is done to help figure out if the area is cancer or not. But as with mammograms, ultrasounds also can have false positive results. If both a mammogram and a breast ultrasound suggest that an area is cancer, a biopsy (an invasive procedure) is usually done to make a final decision on whether the area is cancer or not.
Having a more reliable, non-invasive way to figure out if a suspicious area is breast cancer or not could help women avoid unnecessary biopsies and the stress associated with false positives.
Hemoglobin is the part of a red blood cell that carries oxygen to tissue in the body. If there is a lot of blood in tissue, the amount of hemoglobin in the tissue will high. Breast cancers typically need more oxygen and nutrients compared to healthy tissue. So a suspicious area that is cancer is likely to have more blood flowing through it and so higher amounts of hemoglobin.
But hemoglobin in a cancer will have less oxygen attached to it because cancers tend to use more oxygen than healthy tissue. Optical tomography is an imaging test that aims a beam of infrared light on the suspicious area through the skin. Optical tomography is guided by ultrasound. The infrared light is not radiation and doesn't harm the skin or other tissues. The amount of light reflected back from the suspicious area is based on the amount of hemoglobin in the area and how much oxygen the hemoglobin has attached to it. Compared to areas that aren't cancer, breast cancers have more hemoglobin with less oxygen in them.
In this study, 178 women had a breast biopsy because of a suspicious area in the breast that was found by a mammogram or a breast ultrasound. Before biopsy, all the women also had optical tomography of the suspicious area. The results suggest that optical tomography was an effective way to decide if an area was cancer or not, especially if the suspicious area is small.
For smaller suspicious areas:
- 92% of cancers were identified correctly as cancer
- 81% of the time when optical tomography suggested an area was cancer, the biopsy confirmed it was cancer
- 97% of the time when optical tomography suggested an area wasn't cancer, the biopsy confirmed it wasn't cancer
For larger suspicious areas:
- 75% of cancers were identified correctly as cancer
- 69% of the time when optical tomography suggested an area was cancer, the biopsy confirmed it was cancer
- 95% of the time when optical tomography suggested an area wasn't cancer, the biopsy confirmed it wasn't cancer
Optical tomography also may be able to help monitor how well advanced-stage breast cancers respond to treatment.
While these results offer promise, much more research is needed before doctors know how optical tomography can best be used to evaluate suspicious breast areas found by a mammogram or a breast ultrasound.
Stay tuned to Breastcancer.org for the latest information on new ways to detect and treat breast cancer.
Please help Breastcancer.org bring you the latest news on screening and testing by making a tax-deductible donation today.